Catheter guide wire with short spring tip and method of using the same

ABSTRACT

Guide wire and method for insertion and use of a catheter. The guide wire has a shaft of substantially smaller diameter than the luminal opening, with a flexible coil at one end of the shaft. The guide wire is inserted into the cardiovascular system, and the catheter is advanced along the guide wire to the desired position, with the flexible coil outside the distal end of the catheter. An annular passageway is formed between the shaft and the wall of the luminal opening, and fluids are passed through this passageway while the guide wire is within the catheter. A marker of radio opaque material is provided at the distal end of the guide wire so that the position of the wire can be accurately determined even though the wire itself may be too small to be visible with a fluoroscope.

This invention pertains generally to the insertion of catheters into thecardiovascular system, and more particularly to a guide wire and methodfor inserting and using a catheter.

Guide wires heretofore utilized in the insertion of catheters into thecardiovascular system have included an elongated wire core surrounded bya helically wrapped outer wire of smaller diameter than the luminalopenings of the catheters with which they are employed. With dilationcatheters for use in the coronary vessels and catheters of relativelysmall diameter (e.g., 0.020 inch or less), the guide wire is onlyslightly smaller than the luminal opening, and the guide wire must beremoved before any fluid is passed through the catheter. It hasgenerally not been possible to make the guide wire smaller because itmight not have sufficient torsional rigidity to permit it to be steeredinto the cardiovascular system. In addition, the smaller wire mightpuncture the wall of the artery or other surrounding tissue.

Another problem which catheters of relatively small diameter isdetermining the position of the guide wire. Larger guide wires aregenerally visible with a fluoroscope or other radiographic instrument,but with the smaller catheters, the guide wires may be too small to beseen in this manner.

It is in general an object of the invention to provide a new andimproved guide wire and method for the insertion and use of cathetersinto the cardiovascular system.

Another object of the invention is to provide a guide wire and method ofthe above character in which the guide wire remains in the catheterwhile the catheter is in use.

These and other objects are achieved in accordance with the invention byproviding a guide wire having an elongated shaft of relatively rigidmaterial and a helical coil at the distal end of the shaft. The guidewire is inserted into the cardiovascular system, and the catheter isadvanced along the guide wire to the desired position, with the helicalcoil outside the distal end of the catheter. The shaft of the guide wireis substantially smaller than the luminal opening of the catheter, andfluids are passed through the luminal opening while the guide wire isstill in place. A marker of radio opaque material is provided at thedistal end of the guide wire so that the position of the wire can beaccurately determined even though the wire itself may be too small to bevisible with a fluoroscope.

FIG. 1 is a side elevational view of a catheter and a guide wireincorporating the invention.

FIG. 2 is an enlarged fragmentary centerline sectional view of thedistal end portion of the guide wire in the embodiment of FIG. 1.

FIG. 3 is a fragmentary elevational view of the tip portion of the guidewire of FIG. 1, illustrating the manner in which the tip can be shapedto facilitate insertion into a given artery.

FIG. 4 is an enlarged, fragmentary centerline sectional view of anotherembodiment of a guide wire incorporating the invention.

In FIG. 1, the guide wire 11 is illustrated in connection with acatheter 12 having a proximal end 13 and a distal end 14. The cathetercomprises an elongated tubular body of relatively flexible materialhaving an axially etending luminal opening or passageway 16, with aconnector fitting 17 at the proximal end of the tubular body. Thecatheter can be of any desired type, for example, a dilation catheterhaving a inflatable balloon toward the distal end thereof.

Guide wire 11 comprises an elongated, relatively rigid shaft 21 having aproximal end 22 and a distal end 23, with a relatively flexible helicalcoil or spring 24 extending axially from the distal end of the shaft.The cross-sectional area of the shaft is substantially smaller than theluminal opening of the catheter so that fluids can pass freely betweenthe shaft and the wall of the luminal opening, and the outer diameter ofthe helical winding is greater than the diameter of the shaft but smallenough to pass through the luminal opening. In one presently preferredembodiment for use with a catheter having a luminal opening of 0.020inch, for example, the shaft has a diameter on the order of 0.008 inchand the helical coil has an outer diameter on the order of 0.018 inch.The coil is relatively short compared to the overall length of the guidewire, and shaft 21 is substantially longer than the coil. In onepresently preferred embodiment, for example, the guide wire has anoverall length on the order of 175 cm, and the helical coil has a lengthon the order of 4 cm.

Shaft 21 and helical coil 24 are each fabricated of a suitable materialsuch as stainless steel wire, and in the embodiment of FIG. 1 the distalend portion of the shaft is tapered to provide a gradual transition inflexibility between the very flexible coil and the stiffer shaft. Inthis particular embodiment, the tapered portion of the shaft extends allthe way to the distal end of the coil, but it can terminate before theend, if desired.

The coil and shaft are bonded together by suitable means such asbrazing, welding or soldering, as indicated at 29, in the region of theoverlap. If desired, the bond can be made with a radio opaque materialto make the tip of the wire visible to a fluoroscope or otherconventional radiographic instrument. The radio opaque materialpreferably has a density of at least 13 gm/cm³, and suitable materialsinclude gold, tantalum, tungsten, platinum, iridium, rhenium and alloysof these materials. One presently preferred material is an alloycontaining on the order of about 80% gold, 12% silver, and 8% copper andzinc. If desired, coil 24 itself can be fabricated of a radio opaquematerial such as tungsten, tantalum, platinum, gold or an alloy thereofto make the entire coil visible to a fluoroscope.

A relatively smooth, rounded tip 31 is provided at the distal end ofhelical coil to facilitate insertion of the wire into the cardiovascularsystem without damage to the surrounding tissue. If the embodimentillustrated, this tip comprises a plug which is inserted partially intothe distal end portion of coil 24 and heated to form a bond with thecoil and the tip of shaft 21. This plug can also be fabricated of aradio opaque material to make the tip visible to a fluoroscope or otherradiographic instrument. Alternatively, the rounded tip can be formed byfusing the distal end of the wire forming the helical coil into thedesired rounded shape.

In the embodiment of FIG. 1, connections to the proximal ends of guidewire 11 and catheter 12 are made through a side arm adapter 36 having anaxially extending body 37 and a side arm 38 which extends at an anglefrom the body. The connector fitting 17 at the proximal end of thecatheter is connected to one end of the adapter body by suitableconnector 39, and the luminal opening of the catheter is in fluidcommunication with the chamber formed within the adapter. The guide wireextends axially through the adapter body, and a control knob 41 isaffixed to the end of the wire beyond the adapter. An O-ring assembly 42provides a fluid-tight seal about the guide wire at the rear of theadapter body while permitting the wire to be rotated within the body.Communication with the passageway of the catheter is provided throughside arm 38, and suitable appliances can be connected to the side armfor introducing fluids into or receiving fluids from the catheter.

Operation and use of the guide wire, and therein the method of theinvention, are as follows. The guide wire is inserted into the luminalopening of the catheter, and the guide wire and the catheter areinserted together into the cardiovascular system, with helical coil 24extending from the distal end of the catheter. The guide wire andcatheter can be inserted either directly into the system or through aguiding catheter, as desired. The torsional rigidity of shaft 21 permitsthe guide wire to be turned or steered by rotating control knob 41, andthe flexibility of coil 24 facilitates movement of the wire into theartery or other passageway in the body without damage to the surroundingtissue. The position of the wire is determined by monitoring the radioopaque marker or markers at the distal end with a fluoroscope or otherradiographic instrument. The catheter is advanced along the wire untilit is in the desired position. Because of the relatively small diameterof shaft 21 compared to the cross-sectional area of the luminal opening,fluids can be passed through the catheter without removing the guidewire. For example, a contrast material or dye can be introduced throughthe annular passageway formed between the shaft of the guide wire andthe wall of the luminal opening, and pressure measurements can be madethrough this same passageway.

As illustrated in FIG. 3, coil 24 can be bent in any suitable manner tofacilitate steering of the wire into a side branch of the cardiovascularsystem. The angle of the bend can be chosen in accordance with the angleof the branch into which the guide wire is to be inserted.

The embodiment of FIG. 4 is generally similar to the embodiment of FIGS.1-2, and like reference numerals designate corresponding elements in thetwo embodiments. In the embodiment of FIG. 4, the tapered end portion 23of the shaft 21 terminates prior to the distal end of coil 24, and thewindings toward the distal end of the coil are spaced apart to provide atip which is substantially more flexible than the remainder of the guidewire. A safety wire 36 extends between the distal end of shaft 21 andthe distal end of coil 24, and is fabricated of a material stronger thanthe coil. This wire prevents the coil from being overstretched or brokenin use, and it also facilitates the shaping of coil 24 into variouscurves for steering into side branches of the cardiovascular system.Suitable materials for the safety wire include tungsten and other metalsor alloys stronger than stainless steel. In one presently preferredembodiment, the wire comprises a flat tungsten ribbon having a generallyrectanguar cross-section, with a width of about 0.003 inch and athickness of about 0.001 inch. This ribbon allows the coil to remainextremely flexible and helps the coil retain a curvature to which it isformed. The safety wire is bonded both to shaft 21 and to end plug 31,and in the embodiment illustrated, the proximal end of the safety wireis secured by the same bond 29 that affixes the coil to the shaft.Alternatively, if desired, the proximal end of the safety wire can beaffixed to the tapered portion of the shaft. Operation and use of theembodiment of FIG. 4 is similar to that described above.

It is apparent from the foregoing that a new and improved guide wire andmethod of using the same have been provided. While only certainpresently preferred embodiments have been described in detail, as willbe apparent to those familiar with the art, certain changes andmodifications can be made without departing from the scope of theinvention as defined by the following claims.

We claim: .[.1. In a guide wire for use in the placement of a catheterin the cardiovascular system, an elongated shaft of relatively rigidmaterial having proximal and distal ends and a cross-sectional areasubstantially smaller than the luminal opening in the catheter, arelatively flexible helical coil having proximal and distal ends, saidcoil having an outer diameter slightly smaller than the diameter of theluminal opening and a length substantially less than the length of theshaft, the distal end portion of the shaft extending into the coil butterminating short of the distal end of the coil, the portion of theshaft extending into the coil being tapered to provide a gradualtransition in flexibility of the shaft, means for bonding the proximalend of the coil to the shaft and a flexible safety wire disposedinteriorally of the coil and having one end bonded to the distalextremity of the shaft and having the other end bonded to the distalextremity of the coil..].
 2. A guide wire as in claim .[.1.]. .Iadd.17.Iaddend.wherein the safety wire is formed as a flat ribbon having agenerally rectangular cross section.
 3. A guide wire as in claim .[.1.]..Iadd.17 .Iaddend.together with a relatively smooth rounded tip disposedat the distal extremity of the coil.
 4. A guide wire as in claim .[.1.]..Iadd.17 .Iaddend.together with a radio opaque marker formed of radioopaque material carried by the shaft adjacent the distal end of theshaft.
 5. A guide wire as in claim 4 wherein the radio opaque materialhas a density of at least 13 gm/cm³.
 6. A guide wire a in claim 5wherein the radio opaque material includes an element selected from thegroup consisting of gold, tantalumm, tungsten, platinum, iridium,rhenium and alloys thereof.
 7. A guide wire as in claim 6 wherein theradio opaque material comprises an alloy containing on the order of 80%gold, 12% siliver, and 8% copper and zinc.
 8. A guide wire as in claim.[.1.]. .Iadd.17 .Iaddend.wherein the helical coil is formed of a radioopaque material.
 9. .[.In apparatus.]. .Iadd.A dilatation catheterassembly .Iaddend.for use in the cardiovascular system.[.,.]. .Iadd.of apatient comprising .Iaddend.an elongated, relatively flexible catheterhaving a wall defining an axially extending .[.luminal opening.]..Iadd.lumen .Iaddend.and a guide wire extending through the .[.luminalopening.]. .Iadd.lumen .Iaddend.and having a .[.cross-sectional area.]..Iadd.diameter .Iaddend.substantially smaller than the .[.luminalopening.]. .Iadd.lumen .Iaddend.so that fluids can pass freely betweenthe guide wire and the wall defining the .[.luminal opening.]..Iadd.lumen.Iaddend., said guide wire comprising an elongated shaft ofrelatively rigid material having proximal and distal ends and a.[.cross-sectional area.]. .Iadd.diameter .Iaddend.substantially smallerthan .[.the luminal opening in the catheter.]. .Iadd.0.02 inch.Iaddend.,a relatively flexible helical coil having proximal and distal ends, saidcoil having an outer diameter slightly smaller than .[.the diameter ofthe luminal opening.]. .Iadd.0.02 inch and substantially larger than thediameter of the shaft .Iaddend.and a length substantially less than thelength of the shaft, the distal end portion of the shaft extending intothe helical coil but terminating short of the distal end of the coil,the portion of the shaft extending into the coil being tapered toprovide a gradual transition in flexibility of the shaft, means forbonding the proximal end of the coil to the shaft and a flexible safetywire disposed interiorally of the coil and having one end bonded to thedistal extremity of the shaft and having the other end bonded to thedistal extremity of the coil.
 10. Apparatus as in claim 9 wherein thesafety wire is formed as a flat ribbon having a generally rectangularcross section.
 11. Apparatus as in claim 9 wherein the luminal openinghas a diameter on the order of 0.020 inch, the guide wire shaft has adiameter on the order of 0.008 inch, and the helical coil has a diameteron the order of 0.018 inch.
 12. Apparatus as in claim 9 together with aradio opaque marker formed of radio opaque material carried by the shaftadjacent the distal end of the shaft.
 13. Apparatus as in claim 12wherein the radio opaque material has a density of at least 13 gm/cm³.14. Apparatus as in claim 12 wherein the radio opaque material includesan element selected from the group consisting of gold, tantalum,tungsten, platinum, iridium, rhenium and alloys thereof.
 15. Apparatusas in claim 12 wherein the radio opaque material comprises an alloycontaining on the order of 80% gold, 12% silver, and 8% copper and zinc.16. The apparatus of claim 12 wherein the helical coil is formed of aradio opaque material. .Iadd.17. A guide wire for use in the placementof a catheter having an inner lumen extending therein into a patient'scardiovascular system comprising:a) an elongated shaft of relativelyrigid material having proximal and distal ends and a diametersubstantially smaller than the diameter of the inner lumen; b) arelatively flexible helical coil having proximal and distal ends and anouter diameter slightly smaller than 0.02 inch and substantially largerthan the diameter of the shaft and a length substantially less than thelength of the shaft, the distal end portion of the shaft being taperedto provide a gradual transition in flexibility of the shaft and thetapered portion and extending into the coil but terminating short of thedistal end of the coil; c) means for bonding the proximal end of thecoil to the shaft; and d) a flexible safety wire disposed interiorly ofthe coil and having one end bonded to the distal extremity of the shaftand having the other end bonded to the distal extremity of the coil..Iaddend.